Optimal Range Research Articles

Ultrasonic tool shank with multiple vibration mode for micro-nano drilling: Design, optimization and experiment

The machining effects of hole drilling is limited by merely changing the amplitude. Adjusting ultrasonic vibration frequency to expand the matching range of machining parameters optimization is necessary to improve hole drilling effects. Therefore, the design, optimization, and experiment evaluation for a novel integrated, fined, low-cost dual-frequency ultrasonic tool shank is proposed, which can work in three vibration modes for micro-nano precision drilling. The principle of the dual-frequency ultrasonic transducer is introduced. The electro-mechanical equivalent circuit model with step horn is applied to study the dual-frequency characteristics. The transducer displacement equation model based on the wave equation theory is deduced to find the shared vibration node of the first and third frequency. Sensitivity analysis by equivalent circuit model and Finite element method (FEM) simulation of the key parameter is both conducted to optimize ultrasonic transducer geometry dimension. The vibration node of mounting flange is specified in an identical position for the dual vibration modes. A prototype of ultrasonic tool shank is fabricated and evaluated in experiments. It demonstrates that the dual working frequency of the ultrasonic transducer is 34.9 kHz and 104.5 kHz in the first and third mode resonant vibration, which is benefit to the low and high frequency drilling. Three working modes of the low, high, and coupling frequency vibration is measured by a self-developed ultrasonic generator. When 40 V voltage is excited, the vibration amplitudes of the low and high frequency are 17.8 µm, and 9.3 µm, respectively, which can meet with the drilling requirement. Moreover, the coupling vibration with the low and high mode are excited simultaneously, and the motion trajectory of the coupling vibration is observed in a “M” shape, which is a novel trajectory for the precision micro-nano drilling. Micro drilling experiments show that the 35 kHz ultrasonic vibration drilling can achieve better machining effect than conventional drilling (CD). The 105 kHz ultrasonic drilling outperforms the CD, 35 kHz and coupling ultrasonic drilling at cutting force reduction. The coupling ultrasonic vibration drilling achieves the lowest chipping diameter. It is to be noted that the 105 kHz-8 µm produce the fined smoothly surface. The 35 kHz, 105 kHz and coupling ultrasonic drilling can produce better surface micro morphology with less quantity and size of craters than that of CD.

Ratiometric NIR cell membrane-targeted probe for monitoring cell membrane polarity and tumor application

The investigation of cell membrane polarity is critical to determining cell physiological states and related disease for diagnosis and treatment. Herein, a ratiometric NIR cell membrane-targeted fluorescent probe, Cy-C12-MpN, was designed and synthesized to assess cell membrane polarity, which has an amphiphilic structure consisting of a dodecyl unit and a quaternary ammonium unit. It exhibited changes in emission wavelength and fluorescence intensity with the changes in polarity of the solution. It can use the ratio signal of the two peaks to report the polarity difference in its environment. The self-tuning of the probe internal system ensures the reliability of the test results and can be a semi-quantitative detection method. Indeed, in vitro polarity test, the ratio signal reported by Cy-C12-MpN had an optimal linear range with respect to polarity. Cell imaging illustrated the excellent cell membrane-targeted ability of Cy-C12-MpN, as it can rapidly target the cell membrane within 30 s and still anchor at it well after 1 hr. Moreover, Cy-C12-MpN showed that cell membrane polarity decreases after cells become cancerous, and observed the changes in cell membrane polarity caused by homeostatic membrane response stimulated by polyunsaturated fatty acids firstly. Imaging in vivo demonstrated the ability of Cy-C12-MpN to distinguish between tumor cells and normal cells, and further demonstrated that tumor cells have lower cell membrane polarity. In summary, the accuracy of the ratio detection of the probe Cy-C12-MpN and its excellent cell membrane targeting ability reveal reliable results that can provide very useful insights for cancer research.

A Comparative Study of Machine Learning Methods for Baby Cry Detection Using MFCC Features

The vocalization of infants, commonly known as baby crying, represents one of the primary means by which infants effectively communicate their needs and emotional states to adults. While the act of crying can yield crucial insights into the well-being and comfort of a baby, there exists a dearth of research specifically investigating the influence of the audio range within a baby cry on research outcomes. The core problem of research is the lack of research on the influence of audio range on baby cry classification on machine learning. The purpose of this study is to ascertain the impact of the duration of an infant’s cry on the outcomes of machine learning classification and to gain knowledge regarding the accuracy of results F1 score obtained through the utilization of the machine learning method. The contribution is to enrich an understanding of the application of classification and feature selection in audio datasets, particulary in the context of baby cry audio. The utilized dataset, known as donate-a-cry-corpus, encompasses five distinct data classes and possesses a duration of seven seconds. The employed methodology consists of the spectrogram technique, cross-validation for data partitioning, MFCC feature extraction with 10, 20, and 30 coefficients, as well as machine learning models including Support Vector Machine, Random Forest, and Naïve Bayes. The findings of this study reveal that the Random Forest model achieved an accuracy of 0.844 and an F1 score of 0.773 when 10 MFCC coefficients were utilized and the optimal audio range was set at six seconds. Furthermore, the Support Vector Machine model with an RBF kernel yielded an accuracy of 0.836 and an F1 score of 0.761, while the Naïve Bayes model achieved an accuracy 0.538 and F1 score of 0.539. Notably, no discernible differences were observed when evaluating the Support Vector Machine and Naïve Bayes methods across the 1-7 second time trial. The implication of this research is to establish a foundation for the advancement of premature illness identification techniques grounded in the vocalizations of infants, thereby facilitating swifter diagnostic processes for pediatric practitioners.

Impact of steam pressure toasting time on the alpha helix to beta sheet ratios, nutritional value, protein and carbohydrate subfractions, and rumen fermentation parameters of Faba bean seeds for dairy cattle

The use of Faba bean (Vicia faba) seeds (FBS) as a potential feed ingredient for ruminants has been previously evaluated. However, the effects on nutrient supply and degradability linked to protein secondary structure ratios after different steam pressure toasting (SPT) times are scarce. This study aimed to determine the role of varying alpha-helix to beta-sheet ratios induced by SPT duration on the nutritional value of Snowbird FBS in dairy cattle. Fifteen samples (1 variety × 3 years × 5 treatments) were analyzed for protein secondary structures and nutrient composition. The dry matter (DM), crude protein (CP), starch, and neutral detergent fibre-assayed with a heat stable amylase and expressed inclusive of residual ash (aNDF) contents in raw seeds were 914, 286, 328, and 179 g/kg DM, respectively. The averaged DM, CP, starch, and aNDF in the SPT-processed seeds were 904, 292, 374, and 405 g/kg DM, respectively. Soluble crude protein was about five times higher in raw seeds (239 g/kg DM) compared to steam-pressure toasted seeds (avg. 51 g/kg DM) (P < 0.01). The total digestible nutrients (TDN1x) and energy values gradually decreased as SPT time increased (P < 0.01). Hence, the TDN1x in the raw seeds was 832 g/kg DM, while the values at 30, 60, 90, and 120 min were lower by 2.78, 3.87, 6.44, and 7.71 units, respectively. The NEL3x reduced from 2.03 in raw seeds to 1.82 Mcal/kg (P < 0.01). The effective degradability (ED) of nutrients decreased with SPT duration from 0 to 120 min. Hence, the EDDM reduced from 692 to 357 g/kg DM (P < 0.01), the EDCP from 224 to 67 g/kg DM (P < 0.01), and the EDST from 237 to 129 g/kg DM (P = 0.01). Steam pressure toasting from 30 and up to 60 min might be the optimal range for processing FBS (Snowbird var). These findings could be supported by a post-ruminal evaluation of the nutrients that escaped ruminal fermentation.

Railway sleeper vibration measurement by train‐borne laser Doppler vibrometer and its speed‐dependent characteristics

AbstractA train‐borne laser Doppler vibrometer (LDV) directly measures the dynamic response of railway track components from a moving train, which has the potential to complement existing train‐borne technologies for railway track monitoring. This paper proposes a holistic methodology to characterize train‐borne LDV measurements by combining computer‐aided approaches and real‐life measurements. The focus is on the speed‐dependent characteristics because the train speed affects the intensity of railway sleeper vibrations and the intensity of speckle noise, which further affects the quality and usability of the measured signals. First, numerical models are established and validated to simulate sleeper vibrations and speckle noise separately. Then, a vibration–noise separation method is proposed to effectively extract speckle noise and structural vibrations from LDV signals measured at different speeds. The parameters of the separation method are tuned using simulation signals. The method is then validated using laboratory measurements in a vehicle‐track test rig and applied to field measurements on a railway track in Rotterdam, the Netherlands. Further, the speed‐dependent characteristics of train‐borne LDV measurement are determined by analyzing the competition between sleeper vibrations and speckle noise at different speeds. Simulation and measurement results show that an optimal speed range yields the highest signal‐to‐noise ratio, which varies for different track structures, measurement configurations, and operational conditions. The findings demonstrate the potential of train‐borne LDV for large‐scale rail infrastructure monitoring.

The preoptic area and dorsal habenula jointly support homeostatic navigation in larval zebrafish

Animals must maintain physiological processes within an optimal temperature range despite changes in their environment. Through behavioral assays, whole-brain functional imaging, and neural ablations, we show that larval zebrafish, an ectothermic vertebrate, achieves thermoregulation through homeostatic navigation-non-directional and directional movements toward the temperature closest to its physiological setpoint. A brain-wide circuit encompassing several brain regions enables this behavior. We identified the preoptic area of the hypothalamus (PoA) as a key brain structure in triggering non-directional reorientation when thermal conditions are worsening. This result shows an evolutionary conserved role of the PoA as principal thermoregulator of the brain also in ectotherms. We further show that the habenula (Hb)-interpeduncular nucleus (IPN) circuit retains a short-term memory of the sensory history to support the generation of coherent directed movements even in the absence of continuous sensory cues. We finally provide evidence that this circuit may not be exclusive for temperature but may convey a more abstract representation of relative valence of physiologically meaningful stimuli regardless of their specific identity to enable homeostatic navigation.

Thermo‐hydraulic performance investigation of solar air heater duct having staggered D‐shaped ribs: Numerical approach

AbstractThe thermohydraulic performance (THP) of a solar air heater (SAH) duct with staggered D‐shaped ribs as roughness geometry is examined in this work using three‐dimensional numerical investigation. The investigation is carried out at roughness parameters of radius of rib to transverse pitch (r/Ptv) ratios of 0.1–0.35 and longitudinal pitch to radius of rib (Plg/r) ratios of 4–10 under varied operating circumstances of Reynolds number (Re) from 10,200 to 20,200. The maximum Nusselt number (Nu) is obtained to be 81.3 at Re of 20,200, r/Ptv as 0.1, and Plg/r as 4. In contrast, the maximum friction factor (f) is obtained to be 0.0169 at Re of 10,200, r/Ptv as 0.35, and Plg/r as 4. In the range of parameters examined, the maximum enhancement in Nusselt number (Nu/Nus) is observed to be 1.35 at an optimal parameter of r/Ptv as 0.1, Plg/r as 4, and Re as 10,200. Correspondingly, the enhancement in the friction factor (f/fs) at this optimum parameter is 1.87. The maximum value of the THP parameter is found to be 1.1 at the same optimum range of parameters. In further analysis, correlations were developed for Nusselt number (Nu) and friction factor (f) in terms of r/Ptv, Plg/r, and Re with a deviation of ±2% and ±1.5%, respectively.

The buildability and flexural properties of 3D printed recycled mortar reinforced with synchronized steel cable under different reinforcement ratios

This study achieved the synchronized reinforcement of 3D printed mortar with steel cables by modifying the printing equipment. Recycled sintered brick powder replaced 30 % of cement in the 3D printed mortar mixture. The optimal range for the open time was determined through flowability tests and preliminary tests, which ranged from 10 to 40 min. Ways to improve the reinforcement ratio without compromising buildability were explored. The bond strength between the steel cables and the printed mortar was tested and found to be approximately 2–2.5 MPa. The flexural strength of the printed beams with steel cable reinforcement increased by 172%–357 %, and multiple cracks occurred at the mid-span during the failure process. A correction formula for the flexural strength was provided, with calculated values showing an error within 12 % of the test values.

Intensified Phonon Scattering in ZrCoBi Half-Heusler by Noble Metals Doping.

ZrCoBi-based half-Heuslers have great potential in power generation applications because of their high thermoelectric performance in both p- and n-type constituents. In this work, n-type ZrCoBi with improved thermoelectric performance has been realized by intensifying the phonon scattering via noble metal doping, e.g., Pd and Pt doping. The carrier concentration was effectively tuned to the optimal range, and the lattice thermal conductivity was greatly suppressed via the strong strain field and mass fluctuation scattering brought about by the large difference in atomic size and mass between Pd or Pt and Co. Consequently, the state-of-art figure of merit zT ∼1 was achieved in Pd- or Pt-doped ZrCoBi. In addition, the average zTavg values for ZrCo0.95Pd0.05Bi and ZrCo0.925Pt0.075Bi have reached 0.58 and 0.51, respectively, which are higher than those of most of the reported n-type ZrCoBi-based and ZrCoSb-based half-Heusler alloys.

Epigallocatechin gallate (EGCG) nanoselenium application improves tea quality (Camellia sinensis L.) and soil quality index without losing microbial diversity: A pot experiment under field condition

Applying selenium (Se) fertilizer is the only way to alleviate soil Se deficiency. Although effects of nanoselenium foliar application on plant growth and stress resistance have been extensively investigated, soil application of nanoselenium on soil microorganisms and their relationship with crop quality and soil health remains unclear. In this study, a steady-state homogeneous nanoparticle of epigallocatechin gallate Se (ESe) was synthesized, and a pot experiment was conducted applying ESe at five concentrations (0, 1, 10, 50, and 100 mg kg−1) to the tea planattion soil. The study revealed a significant increase in Se concentration in soil and tea with ESe application and identified 2.43–7.8 mg kg−1 as the safe and optimal range for soil application. Specifically, the moderate dose of ESe improved the tea quality [reduced tea polyphenols (TP), increased free amino acids (AA), and reduced TP/AA] and soil quality index (SQI). Besides, in marure tea leaves, antioxidant enzyme activities [promote catalase (CAT) superoxide dismutase (SOD), and peroxidase (POD)] increased, while level of oxidative stress [malondialdehyde (MDA), hydrogen peroxide (H2O2) and superoxide anion (O2−)] decreased with ESe application. The 16S rRNA of the soil bacteria showed that ESe application significantly changed the community structure of soil bacteria but did not alter the diversity of the bacteria and the abundance of dominant taxa (phylum and genus levels). Statistical analysis of the taxonomic and functional profiles (STAMP) detected 21 differential taxa (genus level), mainly low-abundance ones, under the ESe application. Linear regression and random forest (RF) modeling revealed that the low-abundance bacterial taxa were significantly correlated with SQI (R2 = 0.28, p < 0.01) and tea quality (R2 = 0.23–0.37, p < 0.01). Thus, the study's findings suggest that ESe application affects soil and tea quality by modulating the low-abundance taxa in soil. The study also highlights the crucial role of low-abundance bacterial taxa of the rhizosphere in regulating soil functions under the ESe application.

Experimental study on 18650 lithium-ion battery-pack cooling system composed of heat pipe and reciprocating air flow with water mist

Lithium-ion batteries (LIBs) are critical power sources for portable devices, electric vehicles, power grids, and energy-storage systems. Effective thermal management is mandatory for achieving optimal battery performance. Although the air-cooling method has been investigated extensively owing to its simple structure, convenient maintenance, and low cost, it is insufficient for cooling large-scale battery packs because of its limited air-cooling capacity and unsatisfactory temperature uniformity. Thus, a reciprocating spray cooling system comprising a reciprocating air flow channel, heat pipe array, and spray nozzle is proposed herein for the efficient cooling of 18,650 LIB packs. The effects of the inlet air speed, spray frequency, and spray duty cycle on the cooling performance of the reciprocating mist cooling system and the corresponding optimal operating parameter range are analyzed. Additionally, the competitive mechanism between forced air convection and evaporative cooling is discussed. The results indicate that, compared with the case of natural convection cooling, the temperature increment of the battery pack decreases by 32.1 % under reciprocating mist cooling. Meanwhile, the maximum temperature difference reduces to approximately 3.41 °C with 3C of discharge. The spray frequency minimally affects the overall heat dissipation but induces surface temperature fluctuations in individual batteries. Increasing the spray duration per 10 s in a single spray duty cycle can reduce the average temperature of the battery pack by approximately 2 °C. Additionally, the power-allocation scheme affects the heat dissipation of the system. Decreasing the flow rate of spray cooling water and increasing the inlet air speed promote the evaporation of water mist inside the system, thus further improving heat dissipation. This study provides new insights into the design of air-cooled thermal management systems for battery packs.

Fault Diagnosis for Road Heading Bearings Based On a Multiscale Enhanced Cascaded Difference Filter

Abstract In this paper, a novel multiscale morphological filter, called multiscale enhanced cascaded difference filter (MECDF), is proposed for the fault detection of road heading bearings. Firstly, the cascaded morphological operators are established based on the cascade of the basic morphological operators with similar properties, and then the morphological difference operation is introduced to propose the cascaded difference operators. Subsequently, the enhanced cascaded difference operator (ECDO) is constructed through the convolution of cascaded difference operators. Moreover, since the scale range of structure element (SE) also determines the filtering performance of multiscale morphological filter, an improved multiscale analysis method is presented to select the optimal scale range. Finally, the bearing experimental signals are implemented to validate the effectiveness of MECDF. Experimental results testify that the scale range determined by the MECDF is better than other multiscale morphological filters. Meanwhile, the feature extraction capability of ECDO is also better than other existing morphological difference operators.

Effect of tool traverse speed on high strength structural AA6092/17.5 SiCp-T6 AMC friction stir welding

This study systematically explores the impact of Tool Traverse Speed (TTS) in Friction Stir Welding of aerospace-grade AA6092/17.5 SiCp-T6 Aluminium Matrix Composites. The TTS varied in the range of 0.5 to 3.5 mm/s with Tool Rotation Speed and Tool Tilt Angle being constant. Results indicate that the maximum peak temperature is achieved at 0.5 mm/s, gradually decreasing with increasing TTS up to 3.5 mm/s. Significant fluctuations in spindle torque and Z-force are observed, with values doubling between 0.5 mm/s and 3.5 mm/s TTS. Notably, both extremes of TTS exhibit significant tool wear. Examining the microstructure shows that as the TTS increases up to 2 mm/s, there is a reduction in the particle size while the particle density within the matrix rises. Hardness reaches its maximum at 2.75 mm/s, aligning with the best joint performance and impact resistance. Mechanical property evaluations show joint efficiency increasing from 62% at 0.5 mm/s to 90% at 2 mm/s, then decreasing to 60% at 3.5 mm/s TTS. Impact strength follows a similar trend, peaking at 20.7 J at 2.75 mm/s TTS. This study identifies the optimal TTS range of 1.25 mm/s to 2.75 mm/s, striking a balance between improved mechanical performance and microstructural refinement.

Optimization of characteristic parameters of rectangular solar chimney adapted to agricultural greenhouses

In order to build a composite application scenario for the synergistic development of clean energy generation and agricultural production, this research designs a solar chimney equipped with a rectangular collection system according to the structural characteristics of agricultural greenhouses. With collector efficiency as the primary objective and theoretical power as the secondary objective, the infusion angle is designed for the connecting section between the collection system and the chimney from the perspective of reducing the local resistance loss, and the transition factor ζ is introduced to define it accurately. Response surface methodology was then used to analyze the effect of the level of key system characteristics on collector efficiency and static pressure, and a regression model was developed to determine the best combination within the target optimization range. Results show that the infusion angle prevents too much solar energy from being lost in the vortex by reducing the local resistance loss, which increases the collector efficiency of the system. And when the transition factor is 0, the divergence angle is 2.86°, and the inlet height is 0.05 m, the collector efficiency and static pressure reach 48.75 % and −6.1 pa, respectively, which are 213 % and 563 % higher than the original model.

The Effect of Crude Oil Stripped by Surfactant Action and Fluid Free Motion Characteristics in Porous Medium.

The surfactant solution is crucial in facilitating the spontaneous imbibition process for the recovery of oil in tight reservoirs. Further investigation is required to examine the fluid flow in porous mediums and the process of crude oil stripping by a surfactant solution during spontaneous imbibition. Hence, this study aims to determine the free motion properties of oil and water in porous mediums using the finite-element approach to solve the multiphase flow differential equation, taking into account the capillary pressure. An investigation was conducted to examine the impact of oil viscosity and interfacial tension on the mean liquid flow rate and oil volume fraction. An experimental study was conducted to investigate the impact of surface tension, interfacial tension, and wetting angle on crude-oil-stripping efficiency. The findings indicate that the stripped crude oil migrated through porous mediums as individual oil droplets, exhibiting a degree of stochasticity in its motion. When the interfacial tension is reduced, the average velocity of the fluid in the system decreases. The crude oil exhibited a low viscosity, high flow capacity, and a high average flow rate within the system. Once the concentration of the surfactant solution surpasses a specific threshold, it binds with the oil to create colloidal aggregates, resulting in the formation of micelles and influencing the efficiency of the stripping process. As the temperature rises, the oil-stripping efficiency also increases. Simultaneously, an optimal range of wetting angle, surface tension, and interfacial tension could enhance the effectiveness of removing oil using surfactant solutions. The research results of this paper enrich the enhanced oil recovery mechanism of surfactant and are of great significance to the development of tight reservoirs.

Rapid and facile detection of PBTC antiscalant using functionalized polystyrene nanoparticles and latex agglutination

Organophosphate-based compounds, particularly 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC), have been crucial in circulating cooling systems and wastewater treatments as corrosion inhibitors preventing scale deposits in industrial facilities. Employing the reagent within its optimum concentration range is essential for effective performance, minimizing costs and environmental impacts. However, measuring PBTC separately can be challenging due to its functional groups’ similarity to other common molecules found in natural water, necessitating complex procedures. In this study, amine-functionalized polystyrene (PS) latex nanoparticles were synthesized through emulsifier-free emulsion polymerization and utilized as nanosorbents for PBTC detection via a straightforward latex agglutination method. This phenomenon is facilitated by electrostatic and hydrogen bonding interactions between the positively charged layers on the particle’s surface and the negatively charged PBTC molecules. The pH and concentration of the PBTC solution are key factors influencing the adsorption behavior and capacity of the functionalized latex particles. A graphical representation of aggregation domains, dependent on both PBTC concentration and pH, was created. This map serves as an effective tool for detecting PBTC concentration. The resulting particles show great promise for monitoring the concentration range of phosphate additives in water, offering a simple, rapid detection process with low costs and reduced chemical and equipment requirements.

Integrated optimization of dedicated engine and energy management strategy for the plug-in hybrid commercial vehicle at high altitude

To improve fuel efficiency and reduce pollutant emissions of plug-in hybrid commercial vehicles (PHCVs) at high altitude, an integrated optimization of dedicated engine of PHCV (DEP) and energy management strategy (EMS) is performed. Firstly, the physical model of DEP is established using experimental data. Its empirical model is developed through machine learning with samples generated by the physical model. Subsequently, a hybrid model-based successive approximation method is proposed to optimize various combinations of control parameters including fuel injection timing, rail pressure, VGT opening and EGR rate, aiming at reducing brake specific fuel consumption (BSFC) and NOx within the major working zone of DEP. This optimized DEP is then integrated into the PHCV model to collectively optimize EMS at this challenging altitude. Results demonstrate that this method considerably reduces optimization time without compromising model accuracy. Notably, at 4000 m altitude and under the CHTC-C driving cycle, overall BSFC reduces with a minimum of 194.27 g/(kW·h), most brake specific NOx values remain under 7.5 g/(kW·h), and optimal working range broadens. With integrated optimization, the DEP predominantly works in low-fuel consumption and low-emission zone. Consequently, the fuel economy of PHCV improves by 30.03 %, while NOx and CO2 emissions decrease by 35.88 % and 18.05 %, respectively.

Elutriation of fine particles in a pulsed fluidized bed

This paper reported on fine particle elutriation for two different static bed heights of 25 cm and 30 cm in a pulsed fluidized bed. The effects of three types of flow including continuous airflow, on-off pulsed airflow, and pulsed airflow imposed on continuous airflow were investigated. Observations showed that the elutriation fraction extremely increased with gas temporal average velocity and static bed height for continuous airflow, while for pulsed and mixed flows at the same condition the increase was not considerable. The effect of pulse frequency from 0.033 Hz to 0.1 Hz as an optimum range led to an extreme reduction loss of particles for pulsed and mixed airflows compared to continuous airflow even at high gas temporal average velocities. The elutriation rate of mixed airflow at 0.033 Hz and 3Umf for 30 cm static bed height on average was 75% and 35.3% less than continuous and pulsed airflows, respectively.

Analysis of the Effect of Tube Current, Slice Thickness, and Tube Voltage on Ct Scan Image Noise using the Noise Power Spectrum (NPS) Method

This study was conducted to analyze CT scan images in order to determine the effect of tube current, slice thickness, and tube voltage on noise using the Noise Power Spectrum (NPS) method. Moreover, this study was also aimed to identify the optimal range of tube current, slice thickness, and tube voltage values to minimize noise formation in CT scan images while maintaining the safe dose for the patients. The research parameters included variations in tube current values with slice thickness variations, using tube voltages of 80 kV and 120 kV. The tube current (mAs) variations used were 150 mAs, 200 mAs, 250 mAs, 300 mAs, and 350 mAs, while the slice thickness variations were 0.8 mm, 1.6 mm, 3.2 mm, 4.8 mm, and 9.6 mm. A Phillips 16-slice access CT scan with a water phantom was utilized as the material for the research. The obtained image data were analyzed using ImQuest and ImageJ software. The results show that as the variations in tube current (mAs), slice thickness (mm), and tube voltage (mV) increase, the noise values decrease. This was demonstrated by the smallest area under the curve (AUC) values, which were 24.46 variance for the tube current variation at 120 kV and 3.57 variance for the slice thickness variation at 120 kV. Thus, to minimize the noise, it is recommended to increase the tube current, slice thickness, and tube voltage.

PENGARUH KETINGGIAN AIR TERHADAP PERTUMBUHAN DAN KELANGSUNGAN HIDUP BENIH IKAN KOI (CYPRINUS CARPIO)

Koi fish (Cyprinus carpio) is one of the most popular ornamental fish with high economic value and can compete in local and international markets. One of the obstacles in koi fish farming is growth and survival caused by changes in temperature. One of the factors that affect temperature changes is water level. This study aims to determine the effect of water level on the growth and survival of koi fish seeds. This study used an experimental method with a completely randomized design (CRD). There were 4 (four) treatments tested, namely P1 (15 cm) as control, P2 (20 cm), P3 (25 cm), and P4 (30 cm). Each treatment was repeated 3 times, resulting in 12 experimental units. The variables taken were fish length and weight, and water quality (temperature, pH, DO, ammonia). The results showed that. The ideal container water level and can provide the best results to support the growth of koi fish fry is 25 cm. At a water level of 25 cm, weight growth of 0.034 grams/day, length growth of 0.018 cm/day, specific growth rate of 0.021%/day, and survival rate reached 100%. Meanwhile, water quality parameters during the study were in the optimal range, namely temperature 19 - 23 °C, pH 7, dissolved oxygen 5 - 8 mg/L, and ammonia 00.1 - 0.06 mg/L.